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Phenotypic and genetic characterization of Dunaliella (Chlorophyta) from Indian salinas and their diversity

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Relation http://eprints.cmfri.org.in/9300/
 
Title Phenotypic and genetic characterization of
Dunaliella (Chlorophyta) from Indian salinas and
their diversity
 
Creator Preetha, K
Lijo, J
Subin, C S
Vijayan, K K
 
Subject Fish Genetics
 
Description Background: The genus Dunaliella (Class – Chlorophyceae) is widely studied for its tolerance to extreme habitat
conditions, physiological aspects and many biotechnological applications, such as a source of carotenoids and
many other bioactive compounds. Biochemical and molecular characterization is very much essential to fully
explore the properties and possibilities of the new isolates of Dunaliella. In India, hyper saline lakes and salt pans
were reported to bloom with Dunaliella spp. However, except for the economically important D. salina, other
species are rarely characterized taxonomically from India. Present study was conducted to describe Dunaliella strains
from Indian salinas using a combined morphological, physiological and molecular approach with an aim to have a
better understanding on the taxonomy and diversity of this genus from India.
Results: Comparative phenotypic and genetic studies revealed high level of diversity within the Indian Dunaliella
isolates. Species level identification using morphological characteristics clearly delineated two strains of D. salina
with considerable β-carotene content (>20 pg/cell). The variation in 18S rRNA gene size, amplified with MA1-MA2
primers, ranged between ~1800 and ~2650 base pairs, and together with the phylogeny based on ITS gene
sequence provided a pattern, forming five different groups within Indian Dunaliella isolates. Superficial congruency
was observed between ITS and rbcL gene phylogenetic trees with consistent formation of major clades separating
Indian isolates into two distinct clusters, one with D. salina and allied strains, and another one with D. viridis and
allied strains. Further in both the trees, few isolates showed high level of genetic divergence than reported
previously for Dunaliella spp. This indicates the scope of more numbers of clearly defined/unidentified species/subspecies
within Indian Dunaliella isolates.
Conclusion: Present work illustrates Indian Dunaliella strains phenotypically and genetically, and confirms the
presence of not less than five different species (or sub-species) in Indian saline waters, including D. salina and D.
viridis. The study emphasizes the need for a combined morphological, physiological and molecular approach in the
taxonomic studies of Dunaliella.
 
Date 2012
 
Type Article
PeerReviewed
 
Format application/pdf
 
Language en
 
Identifier http://eprints.cmfri.org.in/9300/1/81.pdf
Preetha, K and Lijo, J and Subin, C S and Vijayan, K K (2012) Phenotypic and genetic characterization of Dunaliella (Chlorophyta) from Indian salinas and their diversity. Aquatic Biosystems, 8 (27). pp. 14-16.